Fixed regression from 0.14.0

[jadchaar]

@systemcatch @crsmithdev we need to get this patch pushed ASAP since a recent change broke the install.

Fixes: #598

This other PR I am working on should prevent such as issue from coming up in the future: #597

[codecov-io]

Codecov Report

Merging #599 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #599   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           7      7           
  Lines        1501   1501           
  Branches      225    225           
=====================================
  Hits         1501   1501

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cfafc0e...9d52ef3. Read the comment docs.

[codecov-io]

Codecov Report

Merging #599 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master   #599   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           7      7           
  Lines        1501   1501           
  Branches      225    225           
=====================================
  Hits         1501   1501

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update cfafc0e...fa4f2e4. Read the comment docs.

[asottile]

[jadchaar]

Proof of fix:

1. 

2. The updated setup.py plays well with Tox now in this PR: Updated tox file and changed Travis CI to use tox #597 (Tox uses the packaged version of arrow to run tests).

[systemcatch]

Oh dear, I wonder why that breakage wasn't caught by the tests.

[asottile]

Oh dear, I wonder why that breakage wasn't caught by the tests.

the good news is @jadchaar is setting up tox which will catch packaging issues like this in the future 🎉 (#597)